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Florentinia perforata
Florentinia perforata Firth, 1993, p. 193, 195
NOW Kleithriasphaeridium. Originally Florentinia, subsequently (and now) Kleithriasphaeridium.
Holotype: Firth, 1993, pl.2, figs.1-4
Locus typicus: Upper Maastrichtian Providence Formation, USGS Albany Core, Albany, Georgia. Depth in core: 287.3 m.
Stratum typicum: Late Maastrichtian
Original description: Firth, 1993, p.193-194
Cyst skolochorate, subspherical, bilayered. Wall layers thin, appressed between processes. Endophragm thin, smooth; periphragm thin, microgranulate, gives rise to hollow, tubiform, intratabular processes with circular bases. Process walls faintly striate or fibrous. Processes fairly short, wide, constricted in the middle, flaring distally, with secate or denticulate distal edges. Parasulcul processes thinner than the rest. Paracingular processes flattened, with flattened oval bases. Antapical process commonly longer than others, is either tubiform with flared distal end, or bulbous, with a closed distal end bearing small projections or knobs. Within the flared distal rims of the hollow tubiform processes are thin, perforate walls that cover the open ends. The thin parasulcul processes may or may not have this perforate end-covering. Paratabulation gonyaulacacean, reflected by archeopyle and intratabular processes. Paratabulation is 4", 6", 6c, 5""", ?1p, 1"""", ?3-4s. Archeopyle combination apical and precingular, type tA + P.
Dimensions: Cyst body height: 30.0 - 51.0 Ám (mean 41.8 Ám, sd 8.8 Ám, n=5), Cyst body width: 37.0 - 60.0 Ám (mean 48.2 Ám, sd 8.6 Ám, n=5), Approximate wall thickness (endophragm and periphragm): 0.7-1.0 Ám (n=4), Process length: 13.0 - 29.0 Ám (mean 17.9 Ám, sd 8.7 Ám, n=20), Antapical process length: 18.0 - 29.0 Ám (mean 23.6 Ám, sd 5.5 Ám, n=5).
Discussion: Firth, 1993, p.194
Specimens recovered all display type tA+P archeopyles, the large, wide, hollow processes, one per paraplate, and somewhat larger antapical process characteristic of the genus Florentinia. Florentinia mantellii and Florentinia cooksoniae resemble F. perforata superficially in the shape of their processes, but differ by having open ended, not covered, tubiform processes. The perforate wall covering the ends of the processes distinguishes F. perforata from all other reported species of Florentinia.
Ioannides (1986) assigned dinocysts to Florentinia? mantellii and to Florentinia? sp. His plate 13, fig. 6 shows the distal end of a process from the latter form, clearly showing the perforate sieve-like structure covering the end of the process. The caption for plate 13, fig. 6 states that this perforate, closed distal end is "a structure seen in many processes of both F.? sp. and F.? mantellii". Ioannides distinguished F.? sp. from F.? mantellii by its wider, parallel sided processes, and indicated that this may be either an extreme variant of F.? mantellii or a separate species. The presence of the perforate distal cover indicates that some of loannides" material assigned to F.? mantellii is actually F perJorata n. sp. This does not include, however, the cyst shown in pl. 12, fig. 15, which only has an apical archeopyle. The affinity of this specimen would require reexamination to determine the presence of perforate process endcoverings, as well as whether the 3" precingular paraplate shows any indication of contributing to the archeopyle. At present these questions remain unanswered. Also, I have not seen any specimens from Georgia which show the wide, parallel sided processes indicative of loannides" Florentinia? sp. Whether this form is simply a variant of F. perforata, or is morphologically distinct from F. perforata would require a biometric analysis of many specimens of both forms.
NOW Kleithriasphaeridium. Originally Florentinia, subsequently (and now) Kleithriasphaeridium.
Holotype: Firth, 1993, pl.2, figs.1-4
Locus typicus: Upper Maastrichtian Providence Formation, USGS Albany Core, Albany, Georgia. Depth in core: 287.3 m.
Stratum typicum: Late Maastrichtian
Original description: Firth, 1993, p.193-194
Cyst skolochorate, subspherical, bilayered. Wall layers thin, appressed between processes. Endophragm thin, smooth; periphragm thin, microgranulate, gives rise to hollow, tubiform, intratabular processes with circular bases. Process walls faintly striate or fibrous. Processes fairly short, wide, constricted in the middle, flaring distally, with secate or denticulate distal edges. Parasulcul processes thinner than the rest. Paracingular processes flattened, with flattened oval bases. Antapical process commonly longer than others, is either tubiform with flared distal end, or bulbous, with a closed distal end bearing small projections or knobs. Within the flared distal rims of the hollow tubiform processes are thin, perforate walls that cover the open ends. The thin parasulcul processes may or may not have this perforate end-covering. Paratabulation gonyaulacacean, reflected by archeopyle and intratabular processes. Paratabulation is 4", 6", 6c, 5""", ?1p, 1"""", ?3-4s. Archeopyle combination apical and precingular, type tA + P.
Dimensions: Cyst body height: 30.0 - 51.0 Ám (mean 41.8 Ám, sd 8.8 Ám, n=5), Cyst body width: 37.0 - 60.0 Ám (mean 48.2 Ám, sd 8.6 Ám, n=5), Approximate wall thickness (endophragm and periphragm): 0.7-1.0 Ám (n=4), Process length: 13.0 - 29.0 Ám (mean 17.9 Ám, sd 8.7 Ám, n=20), Antapical process length: 18.0 - 29.0 Ám (mean 23.6 Ám, sd 5.5 Ám, n=5).
Discussion: Firth, 1993, p.194
Specimens recovered all display type tA+P archeopyles, the large, wide, hollow processes, one per paraplate, and somewhat larger antapical process characteristic of the genus Florentinia. Florentinia mantellii and Florentinia cooksoniae resemble F. perforata superficially in the shape of their processes, but differ by having open ended, not covered, tubiform processes. The perforate wall covering the ends of the processes distinguishes F. perforata from all other reported species of Florentinia.
Ioannides (1986) assigned dinocysts to Florentinia? mantellii and to Florentinia? sp. His plate 13, fig. 6 shows the distal end of a process from the latter form, clearly showing the perforate sieve-like structure covering the end of the process. The caption for plate 13, fig. 6 states that this perforate, closed distal end is "a structure seen in many processes of both F.? sp. and F.? mantellii". Ioannides distinguished F.? sp. from F.? mantellii by its wider, parallel sided processes, and indicated that this may be either an extreme variant of F.? mantellii or a separate species. The presence of the perforate distal cover indicates that some of loannides" material assigned to F.? mantellii is actually F perJorata n. sp. This does not include, however, the cyst shown in pl. 12, fig. 15, which only has an apical archeopyle. The affinity of this specimen would require reexamination to determine the presence of perforate process endcoverings, as well as whether the 3" precingular paraplate shows any indication of contributing to the archeopyle. At present these questions remain unanswered. Also, I have not seen any specimens from Georgia which show the wide, parallel sided processes indicative of loannides" Florentinia? sp. Whether this form is simply a variant of F. perforata, or is morphologically distinct from F. perforata would require a biometric analysis of many specimens of both forms.